Bisexuality is the romantic and/or sexual attraction or behavior with both men and women, or those of any sex or gender identity.

Humans—and animals—have been bisexual for all of recorded history; the term bisexuality, along with the terms heterosexuality and homosexuality, was created in the 19th century.

A 2009 study published in the Journal of Sexual Medicine found that 3.1% of American adults identified as bisexual, more than the 2.5% that identified as gay or lesbian. However, the number of bisexual individuals is likely higher. According to a Pew research study, just 28% of people who identified as bisexual reported they were open about it.

Many people have a hard time understanding bisexuals and therefore there are many negative attitudes about bisexual people, particularly bisexual men. As a result, many bisexual men don’t tell others about their bisexual experiences because they fear losing relationships or hurting their reputations. Some of these negative perceptions come from within the gay community itself, where it is often thought that bisexual people are just unwilling to say they are gay.

These negative perceptions can have health implications for bisexuals. Brian Dodge, a leading researcher on bisexuality from Indiana University, found that compared to hetero- and homosexual individuals, bisexual people have reported higher rates of depression, anxiety, sexual health concerns, substance use, victimization by violence, and suicidal ideation.

Several celebrities have said they are bisexual including Drew Barrymore, Anna Paquin, Megan Fox and Azealia Banks. Few famous men have come out as bisexual, with the exception of Clive Davis, the music mogul.

As bisexuality becomes more understood and accepted, more people will feel comfortable embracing their bisexual identities.